Java Certificate getExtendedKeyUsage(Certificate certificate)

//package com.java2s;

import java.security.cert.Certificate;

import java.security.cert.CertificateParsingException;
import java.security.cert.X509Certificate;

import java.util.ArrayList;
import java.util.Collections;

import java.util.List;

public class Main {
    public static List<String> getExtendedKeyUsage(Certificate certificate) {
        if (certificate instanceof X509Certificate) {
            final X509Certificate x509 = (X509Certificate) certificate;
            List<String> retval;
            try {
                if (x509.getExtendedKeyUsage() == null) {
                    return Collections.emptyList();
                } else {
                    retval = new ArrayList<>();
                    for (String keyUsage : x509.getExtendedKeyUsage()) {
                        retval.add(keyUsage);
                    }//  w   w  w  . d   e m   o  2   s  . c o  m  
                }
            } catch (CertificateParsingException e) {
                retval = Collections.emptyList();
                e.printStackTrace(); //To change body of catch statement use File | Settings | File Templates.
            }
            return retval;
        }
        return Collections.EMPTY_LIST;
    }
}